Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

pH, Cyanide strength, Agitation, density and obviously Carbon activity

hie....how do the following affect Au adsorption

Au concentration

solution pH

CN concentration 

ionic strength

carbon particle size

Activated carbon is used to recover gold from cyanide leach solutions, owing to its large surface area. There are 3 major mechanisms controlling the rate of gold adsorption onto activated carbon:

1) film diffusion: mass transport of gold cyanide from the bulk solution phase through a hypothetical hydrodynamic boundary layer or film surrounding the carbon particle;

2) pore diffusion: mass transport of the dissolved species in the solution filling the pores; and

3) surface diffusion: migration of the adsorbed molecules along the internal pore walls.

It is generally believed that the initial rate of gold adsorption is controlled by film diffusion, whilst pore or surface diffusion or both in parallel become the dominant mechanism at high gold loadings.

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